Light hypersensitivity is characterized by pain, tearing, reflexive squinting, and/or photophobia in response to changes (typically increases) in illumination. Often a person experiences light hypersensitivity when exposed to sunlight, but sometimes, a patient may experience similar symptoms in response to small changes in illumination such as turning on room lights or even turning on computer monitors. In serious cases, some people suffering light hypersensitivity find it necessary to wear sunglasses or other filters (such as blue-blocker filters) at all times. In the most serious cases, a patient may have to avoid lighted spaces altogether.
Light hypersensitivity has been found in many patient populations including, but not limited to, cataracts or migraines. Light hypersensitivity can also be found in people taking photosensitizing drugs, such as phenothiazines, chloroquine or vidarabine, or medications that affect pupil size, such as amphetamines, atropine, cyclopentolate, phenylepherine, scopolamine, and tropicamide, to name a few. Other patient populations with light hypersensitivity include, but are not limited to a variety of clinical conditions such as refractive surgery, chalazion, glaucoma, iritis, corneal abrasion, corneal ulcer, and uveitis.
A patient with light hypersensitivity is currently classified as “light sensitive” or “photophobic” by clinicians. However, no reliable instrument or method is currently available to measure the degree of light hypersensitivity in a patient. Therefore, it is desirable to have a new device and innovative methods of using such a device, to provide quantitative measurements.